AAAR 32nd Annual Conference
September 30 - October 4, 2013
Oregon Convention Center
Portland, Oregon, USA
Abstract View
Comparison of Culturability and Membrane Integrity Loss of Escherichia Coli during Aerosolization by Four Aerosol Generators
HUAJUN ZHEN, Taewon Han, Donna Fennell, Gediminas Mainelis, Rutgers, The State University of New Jersey
Abstract Number: 120 Working Group: Health Related Aerosols
Abstract Bioaerosol research often requires stable and reliable aerosol generators that could produce high particle concentrations. However, there is still a lack of information about the effect of aerosolization on the physiological status of microorganisms. Here we tested the performance of several liquid bioaerosol generators including a Collison nebulizer, a Liquid-Sparging Aerosolizer (LSA), a C-flow nebulizer and a newly designed Single-Pass Aerosolizer (SPA), which is a single-pass pneumatic nebulizer. We investigated each generator’s ability to preserve the culturability of aerosolized bacteria and to retain the structural integrity of cell membrane at different aerosolization pressures.
The bacteria aerosolized by the four generators were collected using a BioSampler. The amount of cell membrane damage was determined as the Cell Membrane Damage Index, which was expressed as the ratio of cell-released 16S rRNA gene copies in sample liquid versus the entire amount of 16S rRNA gene copies in a bioaerosol sample. The Damage Indices for E. coli aerosolized with the Collison and C-flow nebulizers at 40 psi were significantly higher than the corresponding Indices at nebulization pressures of 5 and 15 psi. However the increased aerosolization pressure for LSA and SPA did not have a substantial impact on cell membrane damage. Increased culturability loss was observed for bacteria aerosolized by Collison Nebulizer and SPA with the increased aerosolization pressure, while no significant change in culturability was found for the other two generators with increased aerosolization pressure. At a constant aerosol concentration of 100 bacteria/cm3, the SPA showed the highest bacterial culturability among the tested generators. Only the Collison nebulizer and SPA achieved aerosol concentrations of 1000 bacteria/cm3, and the SPA outperformed the Collison nebulizer with respect to cell membrane damage. Our results demonstrate that the SPA could be used to produce high bioaerosol concentrations with a relatively low amount of damage to bacterial cells.